1. Technical Field
The present disclosure relates to an optical device and assembly thereof. More particularly, the present disclosure relates to an optical device with optical splitting route.
2. Description of Related Art
When packaging vertical-cavity surface-emitting lasers (VCSEL), a tilted glass reflective mirror is typically used to reflect part of the emitted light to a monitor photodetector (MPD) lying beside the VCSEL. Referring to FIG. 1, which illustrates a conventional VCSEL assembly, several components are required, such as transistor outline (TO)-header, TO-cap with light splitting glass, barrel, and lens etc., which make the assembly complex and expensive.
U.S. Pat. No. 6,888,988 proposes a monolithic all-polymer module, such as that shown in FIG. 2, to simplify package process and reduce cost. The light splitting function is based on an air-gap in polymer. However, the splitting ratio cannot be easily adjusted and the splitting ratio is often polarization-sensitive, since the reflectivity is different for transverse electric (TE) and transverse magnetic (TM) light when light is reflected by a tilted surface.
Therefore, there is a need for a design of optical devices that allows arbitrary splitting ratio to be easily implemented, simplifies assembly process, reduces the number of assembly components, and saves assembly cost.